B cells play central pathogenic roles in many human autoimmune diseases including Systemic Lupus Erythematosus (SLE). Understanding and effectively treating human autoimmunity will require a deep understanding of the antigenic, cellular and molecular events that contribute to the breakdown of B cell tolerance and the downstream events leading to acute clinical disease through the generation of effector cells and to chronic autoimmunity through the formation, maintenance and reactivation of long-lived autoimmune memory. The Emory Autoimmunity Center of Excellence (ACE) U19 proposes an integrated approach to elucidating these central questions through three highly synergistic projects and the use of state-of-the-art technology. The Principal Project (Dr. Sanz, PI), will elucidate the relative participation of naive and memory cells in the generation of antibody secreting cells expanded during acute lupus flares, the antigenic drives responsible for these expansions and the cellular basis of different types of lupus autoantibodies. The Collaborative Agenda (Dr. Boss, PI), will use transcriptional and epigenetic studies to map the signaling pathways responsible for the cellular events addressed in the Principal Project. In turn, these studies will provide a scientific and technological platform that the Emory ACE U19 will extend to other ACE centers to similarly study other immune cell types and human autoimmune diseases. Finally, the Pilot Project (Dr. Jacob, PI), will dissect the molecular determinants responsible for the survival of human long-lived plasma cells. The scientific mission of the Emory ACE U19 will be supported by a well-integrated Administrative Core led by Dr. Sanz who has served in a similar role for more than 10 years as PI of the Rochester ACE. The Emory ACE will also provide major input into the ACE Steering Committee actively contributing to developing the scientific agenda of the network and to the design and implementation of mechanistic studies both through the U19 Collaborative Agenda and the UMI-supported clinical trials. RELEVANCE: The Emory ACE U19 will pursue an integrated approach to the cellular and molecular mechanisms of B cell dysfunction in Human SLE. Through the Collaborative Project, it will enlarge its reach to study other immune cells and autoimmune diseases. The expected results should greatly enhance our ability to diagnose, treat and prevent autoimmune diseases. Principal Project: B Cells in Human SLE Project Leader: Ignacio Sanz DESCRIPTION: SLE is a systemic autoimmune disease characterized by profound B cell abnormalities and multiple autoantibody production. However, despite major advances in the field of human B cell biology, the precise antigenic and cellular mechanisms that underlie the activation, diversification and expansion of B cells in SLE remain poorly understood. Moreover, a precise understanding of the relative participation of different B cell subsets during acute disease exacerbations has been hampered by disease heterogeneity, imprecise B cell phenotyping and the lack of high-throughput technologies needed to define the antigenic forces driving the generation and selection of autoreactive B cells and serum autoantibodies. During the current ACE cycle we have established the tools required to address these questions including multi-dimensional flow cytometry; next generation sequencing (NGS); large scale single cell antibody generation; and bioinformatics platforms for the integrative analysis of high-density immunological, transcriptional and clinical data. Moreover, we have initiated collaborations with expert groups for the study of B cell and ASC epigenetics (Dr. Boss, Collaborative Agenda PI) and for the analysis of serum antibody proteomics (Dr. Cheung; CST). In this Principal Project of the Emory ACE U19, we proposed to build on these accomplishments to dissect the participation of B cell and ASC subsets through the following specific aims: Aim 1. Participation and antigenic selection of different B cell compartments in SLE flares using repertoire analysis by NGS and single cell antibody production; Aim 2. Relative contribution of short-lived and long-lived antibody secreting cells to the SLE serum autoantibody proteome; and Aim 3. Epigenetic and transcriptional control of SLE B cells in conjunction with the Collaborative Project. The work proposed is highly synergistic with the Collaborative Agenda and the Pilot Project and has a high degree of innovation in terms of the questions asked and the experimental approach. The expect results should be of far-reaching significance for our understanding of the pathogenic mechanisms acting upon B cells in human autoimmunity and for the rationale design of safer and more effective therapies. RELEVANCE: This project will provide critical insight into the contribution of different B cells and antibody secreting cells to the autoantibody repertoire and disease process in human SLE. Together with the Collaborative Project, it will also study the epigenome and transcriptional program of autoimmune B cells.